1. Field of the Invention
The present invention relates to a piezoelectric actuator.
2. Description of the Related Art
A piezoelectric actuator causes electromechanical conversion elements to expand and contract with driving signals, and utilizing the expantion and contraction, the piezoelectric actuator generate progressive oscillation waves (hereinafter referred to “progressive wave”) at a driving surface of an elastic body. The piezoelectric actuator produces elliptical motions at the driving surface by the progressive waves, makes the relative movement member which pressingly contucts against wave peaks of the elliptical motions move to generate the driving force (see Japanese Patent Application Publication No. S58-148682)